Treatment of hydrocarbon oils



y 1935. J. G. ALTHER 2,009,128

TREATMENT OF HYDROCARBON OILS Filed March so, 1932 (FRACTIONATOR FURNACE 1,

I9 RECEIVER INVENTOR JOSEPH G. ALTHER Patented July 23, 1935 UNITED STATES PATENT OFFICE 2,009,128 TREATMENT OF HYDROCARBON OILS Joseph G. Alther, Chicago,

versal Oil Products Company,

111., assignor to lUni- Chicago, 111., a

corporation of South Dakota Application March 30, 1932, Serial No. 601,968

1 Claim.

This invention relates to the treatment of hydrocarbon oils and refers more particularly to an improved process and apparatus for the version of hydrocarbon oils to produce maximum yields of good quality motor fuel.

In a process for oils wherein the oil is subjected to cracking perature and substantial superatmospheric COD.-

the conversion of hydrocarbon tempressure in a heating element, the total products thence passed through an unheated reaction zone wherein conversion, particularly of the vaporous products, may continue, vaporous and vaporous products being simultaneously withdrawn from the reaction zone to a reduced sure vaporizing zone where their final separation presoccurs, vapors from the vaporizing zone being subjected to fractionation, their relatively heavy components, condensed by such fractionation,

being returned to the heating element for further conversion while their lighter desirable components, withdrawn from the fractionator as vapors, are condensed and collected; the present invention incorporates the improvement which moval of an intermediate product as a side stream of distillate from the fractionator and the point of removal of the overhead vaporous products which comprise said desirable light distillate and gas.

It is the primary object of the invention to subject the light distillate products of conversion to the refining and cleansing action of steam while they are still in a vaporous state and during their fractionation to permit the removal of a product of good color, odor and stability direct from the cracking system. Inasmuch as the type of cracking process to which the principles of the present invention are here applied is one which produces high yields of motor fuel of the desired boiling range yields of high anti-knock finished motor requiring no further treatment may result the unique combination.

It is often desirable in the practice of the and of high anti-knock value, maximum fuel from present invention to withdraw, from the fractionator of the system, a side stream of distillate which may be reformed under cracking conditions and/or otherwise treated to produce additional yields of good quality motor fuel, or simply to improve its quality. is employed an additional in the use of steam in the fractionator by i When this type of operation advantage may result ntroducing all or a portion of the steam into an accumulated pool of distillate in the fractionator,

which distillate after being subjected to the reboiling action of the steam to free it of entrained desirable low boiling constituents, is withdrawn as 5 the stabilized side stream.

The attached diagrammatic drawing illustrates a specific form of apparatus embodying the features of the present invention. Raw oil charging stock for the process may be supplied through 10 line i and valve 2 to pump 3 from which it is fed through line l and valve 5 to heating element 6. When desired, the raw oil may be preheated in any well known manner, not illustrated in the drawing, for example, by indirect contact with 15 hot vaporous or liquid products of the process prior to its introduction into the heating element.

Heating element 6 is located in a furnace I capable of supplying the required heat to efiect conversion of the oil. The heated oil is dis 20 charged from the heating element through line 8 and valve 9 into reaction chamber in. The heating element and reaction chamber are both preferably maintained at substantially superatmospheric pressure. The total conversion prod- 25 ucts from the heating element pass through chamber II) where particularly the vaporous products are subjected to continued conversion while the liquid products, which pass more rapidly through the chamber, are withdrawn therefrom without prolonged further conversion. Both liquid and vaporous products are withdrawn from chamber in through line H and valve l2 and are introduced into vaporizing chamber l3.

By means of valve l2, the pressure is reduced 3 upon the products passing to chamber I3 and by virtue of the pressure reduction, heat is liberated and the liquid products are subjected to further vaporization. The residual liquid products of the process remaining unvaporized in chamber 0 l3 may be withdrawn therefrom through line I4 and valve H to cooling and storage or to any desired further treatment.

Vapors from chamber l3 pass through line l6 and valve i! to fractionation in fractionator l8, 5 the insufiiciently converted relatively heavy components of the vapors condensed within the fractionator collecting in the lower portion thereof to be withdrawn through line 09 and valve 20 to pump 2| from which they are returned through 50 line 22, valve 23 and line t to further conversion in heating element 6 together with the raw oil charging stock. The light distillate product of the system of the desired end boiling point is withdrawn as vapors from the upper portion of the fractionator and steam is introduced thereto, while the product is still in a vaporous state, in the upper portion of the fractionator through line 24 and valve 25, exerting a purifying and cleansing action upon the vapors in their final stages of fractionation in order to accomplish their removal from the system as a finished motor fuel. The vapors pass from the upper portion of the fractionator through line 26 and valve 21 to condensation and cooling in condenser 28, products from which are withdrawn from line 29 and valve 39 to be collected in receiver 3|. Uncondensable gas may be released from the receiver through line 32 and valve 33. The finished motor fuel product is withdrawn through line 34 and valve 35. The steam is withdrawn from the fractionator with the vapors condensed in condenser 28 and may be removed as water from the receiver through line 36 and valve 3].

It is often desirable in this type of operation to withdraw the total motor fuel product of the system in two streams which are separated in the fractionator. The overhead stream or vapors comprise the relatively light motor fuel components which are of sufficiently good quality with respect to anti-knock value, sulphur content, etc., to require no further treatment and which, in the present invention, have been subjected to the action of steam to assist in their refining. That portion of the motor fuel condensed in the fractionator and removed therefrom as a side stream comprises its heavier components which may require further treatment. This condensate may collect upon a suitable tray or bafile 38 in the fractionator to be withdrawn therefrom through line 39 and valve 40. As a special feature of the invention, all or any portion of the steam utilized in the fractionator may be introduced through line 24' and valve 25' into the pool of condensate accumulated on tray 38, serving the purpose of reboiling this material to free it of entrained desirable light components. In case the feature of utilizing steam for reboiling of the distillate side stream is not utilized it will ordinarily be necessary to employ a sidestripping column 4| to which the side stream may be supplied through line 39 and valve 40. By means 'of a reboiling coil 42, utilizing steam or other suitable heating medium, the flow of which is controlled by valves 43 and 44, reboiling of the side stream may be accomplished in column 4|. The vaporized components of the distillate and side stream may be returned from column 4| to the fractionator through line 45 and valve 46. The stabilized distillate may be removed through line 41 and valve 48 to any desired further treatment.

Conversion temperatures of the order of 850 to 1000" F. may be employed at the outlet from the heating element with superatmospheric pressures ranging, for example from 100 to 800 pounds or thereabouts per square inch. Substantially this same range of pressures may be employed in the reaction chamber while the vaporizing chamber and the succeeding fractionating, condensing and collecting portions of the system are preferably operated at substantially reduced pressure relative to that employed in the reaction chamber, ranging from approximately 100 pounds per square inch down to substantially atmospheric pressure.

As a specific example of the operation of the process of the present invention, the raw .oll charging stock is a 44 A. P. I. gravity Pennsylvania distillate which is subjected together with reflux condensate, from the lower portion'of the fractionator toa temperature of about 950 F. at the outlet from the heating element, a pressure of approximately 400 pounds per square inch is maintained in the heating element and reaction chamber. The vaporizing chamber is maintained under a reduced pressure of approximately pounds per square inch which is substantially equalized in the succeeding portions of the system. The overhead product withdrawn from the fractionator as vapors may represent about 57% of the charging stock. Its boiling range is approximately 87 to 300 F., the color is approximately 30 and the anti-knock value is equivalent to an octane number of approximately 88. The heavier motor fuel fractions withdrawn as the side stream from the fractionator comprises material boiling between approximately 300 to 400 F. This material represents about 20% of the charging stock and is subjected to light sulphuric acid treatment before being blended with the lighter motor fuel fractions. The steam utilized in the fractionator is introduced into the pool of condensate in the fractionator which is subsequently withdrawn as the side stream. The only other products of the system are uncondensable gas, a relatively small amount of heavy residual oil and a negligible amount of coke.

I claim as my invention:

A process for producing good quality motor fuel distillate which comprises cracking hydrocarbon oil and separating resultant vapors from residue, introducing the vapors to a fractionating column and fractionating the same in the lower portion of the column to condense fractions thereof heavier than gasoline, returning said fractions from the lower portion of the column to the cracking step, further fractionating the vapors in the upper portion of the column to form a lighter condensate containing a substantial quantity of the heavy gasoline hydrocarbons while retaining the light gasoline hydrocarbons in vapor form in this part of the column, collecting said lighter condensate at an intermediate point in the column and withdrawing the same therefrom to a stripping zone, introducing steam to the upper portion of the column above the collected lighter condensate and commingling the same therein with the vapors of said light gasoline hydrocarbons, reboiling said lighter condensate in the stripping zone and returning the resultant vapors to the column above the point of introduction of the steam, removing the reboiled lighter condensate from the stripping zone and the steam-treated light gasoline vapors from the top of the column, condensing the withdrawn mixture of steam and light gasoline vapors and separating the hydrocarbon condensate from the water.

JOSEPH G. ALTHER. 

